RPT-U.S. dollar extends gains; euro at 3-month low

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LONDON, Dec 17 (Reuters) - The U.S. dollar extended gains against other major currencies on Thursday as players unwound dollar-short positions ahead of the year-end.

The euro slipped to a new three-month low of $1.4356 EUR=, down 1.2 percent on the day, Reuters data showed.

The Swiss franc also fell to a three-month low of $1.0492 CHF=, or 1 percent lower on the day against the U.S. unit.

The Canadian dollar hit a three-week low against the U.S. dollar at C$1.0714 CAD=D4. The dollar index, which tracks the performance of the greenback versus a basket of six other major currencies, rose to 77.701 .DXY, its highest since early September. (Reporting by London forex team)